Personal Exposure Monitoring of Air Pollutants as an Educational Tool in the GO3 Treks project launched by the Phase I grant, ~2,500 students at 50 schools throughout the U.S. used personal monitors to measure the air pollutants black carbon and ozone along treks of their own design. The ~275 treks were uploaded to blogs in the GO3 website where they were displayed on Google Earth and where students, teachers, GO3 staff and air quality scientists discussed the results. The students learned about the sources, transformations and sinks of air pollutants by acting as citizen scientists, forming and testing their own hypotheses using real scientific instruments. Highlights include comparisons of rural vs. urban exposures, discovery of increased pollution levels during pick-up/drop-off traffic at schools, comparisons of pollutant levels along busy and residential streets, analysis of exposures during commutes to school, a trek at a hydraulic fracturing site, treks from urban areas into the mountains, and investigation of emissions from different types of sources such as lawnmowers and buses. One school explored an area that is known to have an underground coal mine fire and even launched the ozone monitor on a balloon to 30 km (100,000 ft.) where ozone in the stratosphere was measured. We propose to improve upon and expand GO3 Treks in the Phase II project by: 1) implementing a quality assurance (QA) program for GO3 Treks data; 2) developing a universal Personal Air Monitoring Module (PAMM) that will allow any air quality sensor to upload data in real time to GO3 Treks via a smart phone app; 3) expanding the suite of miniaturized instruments available to GO3 Treks to include CO2 and Equivalent PM2.5 in addition to O3 and black carbon; and 4) revising the GO3 online curriculum to be smaller bite-sized modules, each of which can be completing in an hour or less, and awarding digital badges for completion of each module. Individuals, who earn all GO3 Air Quality digital badges, including those awarded for participation in a trek and for achieving a prescribed level of activit on the GO3 network, will be awarded a Mozilla Open Badge that can be included in their digital resume. The commercialization plan expands GO3 Treks to include citizen monitoring by environmental advocates and local government agencies in addition to schools and proposes rental of instruments at a fee of only $50/week. A business model is proposed that provides exponential growth of the project by continuous reinvestment of all but 5% of profit in new inventory. Model results using reasonable assumptions show that in four years GO3 Treks could be grown to annual rentals of ~$3M with servicing of ~10,000 organizations from an inventory of ~2,000 instruments.